1. Field of the Invention
The present invention relates to treadmills, and more particularly but not by way of limitation, to a treadmill having a low-friction coating on the deck portion for enhancing the lubricity and wear characteristics of the deck portion, while at the same time lowering the resistance to belt movement thereacross.
2. History of the Prior Art
Treadmills have long been used in health clubs and the home as exercising devices. Further, the prior art is replete with wear resistance surface coatings. Such coatings are used for many applications including coating planar members adapted for supporting conveyor belts, treadmill belts and the like. In the main, these coatings are adapted for affording durability, long wear and reducing friction as the belt moves across the deck portion of the treadmill. The aspects of low friction and durability allow a conveyor belt or treadmill to operate with greater efficiency and less cost. Likewise, there are a myriad of treadmill designs which incorporate a variety of support surface configurations for reducing friction on the belt. The present invention pertains to this area of technology and provides a marked advance.
Treadmills have been available for many years to those individuals wishing to exercise by running in a confined space. The treadmill generally includes an endless belt having at least one surface with a high coefficient of friction to prevent the user from slipping. The surface beneath the belt has included rollers and smooth planar structures, such as boards, which allow the runner's feet to engage the treadmill surface and move relative to the underlying support. When the treadmill is properly designed, the drive motor is able to maintain the uniformity of speed of the belt with a variety of runner sizes, weights and running styles. Improper wear and/or increased resistance of the belt causes serious problems with such treadmills and can result in overload of the motor and/or personal injury to the user.
The coating of treadmill support surfaces and the underlying surfaces of conveyor belts, moving sidewalks and the like have found widespread recognition as an area in need of technological development. Numerous compositions have been formulated by the prior art for affording strength, durability and reduced friction. These coatings are generally applied directly to the underlying surfaces of the treadmills for preventing the deterioration thereof while affording enhanced low-friction characteristics. One of the measures of treadmill efficiency is the amount of current drawn by the treadmill motor during loading applications. Increases in the amount of current needed to drive a treadmill at a fixed rate indicates a deterioration in the underlying surface resulting in a higher coefficient of friction and oftentimes deleterious wear for both the belt and the surface. Smooth coatings, such as wax finishes, reduce the amount of frictional resistance for a short period of time. However, prolonged use causes substantial wear to the wax and ultimately a wax build up in the system. This leads to decreased surface lubricity of the originally waxed surface.
The prior art is also replete with the teaching of surface coatings and compositions affording strong, resilient surfaces having a low coefficient of friction. One such example is set forth and shown in U.S. Pat. No. 3,726,817 issued in 1973 to Niswonger. A curable surface coating composition is taught therein which comprises an unsaturated polyester resin, natural wax particles and flock. The before-mentioned ingredients are mixed with a curing catalyst, such as methyl ethyl ketone peroxide, and poured or sprayed as a thin film onto the particular substrate. The composition is particularly adapted for use as a skating surface; and the cured coating is waterproof and strongly bonded to the substrate. The specificity with which such compositions are blended is adequately set forth.
The unsaturated polyester resin of the Niswonger composition is of a conventional variety being an organic acid or anhydride thereof, e.g., an alkylene glycol condensation product wherein the acid (anhydride) and glycol are present in approximately equimolar portions. Such resins are generally made by reacting a mixture of aliphatic unsaturated acid or anhydride (such as maleic acid, maleic anhydride or furmaric acid) and a saturated aliphatic acid or aromatic acid or anhydric thereof (such as phthalic acid, phthalic anhydride and the like wherein the mol ratio of unsaturated acid to aromatic or saturated acid is in the range of 2:1 and 1:2). These details are set forth in column 2 of the Niswonger patent.
The wax used is any natural wax which is normally solid and which melts at the temperature reached during the resin curing and thereby distributes itself evenly throughout the coating. It is obviously important to provide an homogeneous coating which the aforesaid compositions provide. The wax therein makes the coating waterproof and it is therein stated that it is believed that the wax acts as a plasticizer and causes the coating to have a lower coefficient of friction than if it were made only of cured resin solution. With the resin solution, wax, and flock a UV stabilizer is blended to form a mixture for uniform application.
Similarly, Koellisch U.S. Pat. No. 4,025,676 teaches a composite skid construction for moving heavy objects. It has been stated to be found that impregnating material, such as a matted or compressed fabric formed of numerous types of synthetic fibers and material including rayon, nylon and polypropylene and polyester, can be impregnated with a wax to greatly enhance the ease in moving supporting objects. Such wax is granulated and is the type used for bowling alleys and the like.
Numerous other patents address coatings for reducing the coefficient of friction on surfaces for purposes of facilitating sliding thereacross. U.S. Pat. Nos. 3,753,769 and 4,058,649, issued to Steiner, disclose a coating material consisting of an interpolymer and a slip agent and/or a cold slip antiblocking finely divided wax. U.S. Pat. No. 4,201,826, issued to Nylander, discloses polyester compositions useful in making multilayer laminates. Glass fiber reinforcements are suggested therein. U.S. Pat. No. 3,498,826, issued to Caroselli et al., discloses the application of a solid organic lubricating material (such as teflon) to fiber glass in combination with a resinous binder. U.S. Pat. No. 3,165,567, issued to Olson, discloses impregnating the surface of a resin with lubricating particles. U.S. Pat. No. 2,784,223, issued to Caroselli, discloses coating glass fibers with a finely divided teflon in a resin. These patent references manifest the interest to which the technology of the prior art has advanced. The utilization of a hard and durable coating provided in a lower coefficient of friction and high lubricity is seen to be desirable. Each composition, however, provides various parameters of durability, hardness, lubricity, impact resistance and wear resistance. For use in treadmills and the like wherein a continuous belt moves over the coated surface with intermittent impact loading thereacross, the aspects of durability and wear resistance in combination with high lubricity are critical considerations.
A permanent coating is thus needed for treadmills, conveyor belts and the like which provides a lower coefficient of friction with high lubricity. The coating composition must be durable and have the propensity to wear evenly while becoming smoother throughout the life of the coated surface. The present invention provides such an advance over the prior art through the utilization of a composition consisting essentially of a polymeric resin, wax and a particulate material selected from the group consisting of metal and melamine, such composition manifesting high lubricity and durability.